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+import toInteger from '../_lib/toInteger/index'
+import addISOWeekYears from '../addISOWeekYears/index'
+import requiredArgs from '../_lib/requiredArgs/index'
+
+/**
+ * @name subISOWeekYears
+ * @category ISO Week-Numbering Year Helpers
+ * @summary Subtract the specified number of ISO week-numbering years from the given date.
+ *
+ * @description
+ * Subtract the specified number of ISO week-numbering years from the given date.
+ *
+ * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
+ *
+ * ### v2.0.0 breaking changes:
+ *
+ * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
+ *
+ * - The function was renamed from `subISOYears` to `subISOWeekYears`.
+ *   "ISO week year" is short for [ISO week-numbering year](https://en.wikipedia.org/wiki/ISO_week_date).
+ *   This change makes the name consistent with
+ *   locale-dependent week-numbering year helpers, e.g., `setWeekYear`.
+ *
+ * @param {Date|Number} date - the date to be changed
+ * @param {Number} amount - the amount of ISO week-numbering years to be subtracted. Positive decimals will be rounded using `Math.floor`, decimals less than zero will be rounded using `Math.ceil`.
+ * @returns {Date} the new date with the ISO week-numbering years subtracted
+ * @throws {TypeError} 2 arguments required
+ *
+ * @example
+ * // Subtract 5 ISO week-numbering years from 1 September 2014:
+ * const result = subISOWeekYears(new Date(2014, 8, 1), 5)
+ * //=> Mon Aug 31 2009 00:00:00
+ */
+export default function subISOWeekYears(dirtyDate: Date | number, dirtyAmount: number) {
+  requiredArgs(2, arguments)
+
+  const amount = toInteger(dirtyAmount)
+  return addISOWeekYears(dirtyDate, -amount)
+}